Thread: Patrol Diffs

Originally Posted by Camo

Spent 1k on a custom dc rear shaft and still had massive vibes.

A single DC would have been the wrong setup for it, probably worse. Because of the diff being a centre offset (drop) it'd need just uni-uni or DC-DC and the flanges setup parrallel. Even if you pointed the diff up to the transfer, there is still misalignment due to the diff being in the centre so a single DC setup wouldn't work.

Originally Posted by Slunnie

A single DC would have been the wrong setup for it, probably worse. Because of the diff being a centre offset (drop) it'd need just uni-uni or DC-DC and the flanges setup parrallel. Even if you pointed the diff up to the transfer, there is still misalignment due to the diff being in the centre so a single DC setup wouldn't work.

That was my thinking as well, as long as the pinions are parallel, it wouldn't matter what line the tailshaft took as that is how uni's are designed to work.

A diff is a diff is a diff. All it does is transfer engine rotation to wheel rotation, so it shouldn't matter what diff is under there, be it a Rangie, GQ or (dare I say it) a Toyota. I understand that the GQ diff is probably the harder to fit as the pumpkin is in the centre, but there are vehicles that come from factory that have the tail shaft running diagonally with just two uni's so it must work.

To an earlier post, I'm not building a comp truck. I'm building a car that I can have fun in and that isnt going to cost the earth. The other factor is that it is not the normal 4WD down this way and I like the way it looks. If I wanted a GQ or an 80, I would have bought one to begin with. To be totally honest, I wasn't actually looking for a Rangie when this one came up, but when it it, it was a bargain and now I have a new found respect for it's ability. I don't want to spend thousands on strengthening the stock diffs, I suppose I really want to show that a competent off road vehicle can be built on a budget. Not including wheels, (as they would need to be purcahsed no matter what the vehicle) this car has cost me less than $3000, including the GQ diffs and another spare car. I would spend that alone on stronger diveline components just to keep everything Landrover.

Originally Posted by Slunnie

A single DC would have been the wrong setup for it, probably worse. Because of the diff being a centre offset (drop) it'd need just uni-uni or DC-DC and the flanges setup parrallel. Even if you pointed the diff up to the transfer, there is still misalignment due to the diff being in the centre so a single DC setup wouldn't work.

Had a high angle uni-uni made as well. Still didn't do much. The angle is massive. Good luck with the conversion.. You are the one that has to drive it. I'm pretty fussy though... Hate any kind of vibes and wobbles.

Was having a think yesterday, what if I ran a Commodore style shaft. Fixed from the TC to a crossmember, then a CV, then down to the diff. The fixed front part runs at the angle across the car, from the CV it is in line. Might be too short to do that though. Depends on how short you could do a uni uni shaft running at a fairly sharp angle.

Quite frankly the only joints that can handle large angles for any length of time are front wheel drive outer CV joints. Get a couple of front drive shafts off something like a V6 Magna and adapt them to each end of a standard slip-jointed drive shaft. Front outer CV's don't have any axial travel so you still need a sliding joint. Nothing a bit of fabbing out of old front drive flanges can't do to connect at the diff and TC.

I think Hardy-Spicer have a DC for this conversion, or talk to Tom Woods in the US.

One of the Deefer 130 boys had Tom make a double DC shaft for his 130 as he couldn't get rid of vibes with the P38 style rear diff.

CVs are certainly the way to go. With a sliding joint and a CV at each end you might even be able to get away with a single shaft. However, given your admitted driving style, weight of the vehicle and high rpm in rugged terrain in low range, the resultant shock loads transmitted down the drive train may still cause distortion of the Patrol diff housing, if the CV joints don't give way before hand...
Have you thought of contacting a specialised driveline shop which does off road stuff. They probably do all sorts of custom jobs and could at least give you some pointers as to what's feasible!
good luck on your quest

I'm not sure if glen dobbins business was continued after his passing, but they had driveshaft CV's (CV's, not DC's) that were built strong.